A novel in-situ aging evaluation method by FTIR and the application to thermal oxidized nitrile rubber

A novel in-situ aging evaluation method with high sensitivity was established. This method allowed simultaneous heating and UV irradiation of a sample under variable atmosphere, and in-situ Fourier transform infrared spectroscopy (FTIR) detection of the atmosphere change in a specially designed sealable cell. This method was applied to the evaluation of aging status of thermal oxidized nitrile rubber (NBR). In-situ FTIR signals of the atmosphere during heating of NBR samples were analyzed and the decrease of absorbances of characteristic bands with aging times were observed. The absorbances of the selected characteristic band (-NCS band) were correlated to the mechanical properties including recovery from bending (RFB), Young's modulus and elongation at break of the samples. Perfect linear relations between the absorbances of the characteristic band and mechanical properties were obtained. The method was extremely sensitive and had high sensitivity. Stability information or aging status of NBR could be obtained within several hours, and sample changes in very early stage (0-36 h) could be distinguished. The flexible and variable testing conditions provided the new method with great potential.